There is evidence indicating that antigenic peptides are bound to chaperonin proteins and transported to the MHC class I by these chaperonins. More experimental results are needed to establish the detailed mechanism. We will use mass spectrometry based techniques to analyze the chaperonin protein GRP 94/peptides complex and peptides isolated from GRP 94 to address this challenge. The objectives of this research project are: 1. Obtain first-hand evidence that antigenic peptides are complexed with GRP 94. 2. Determine the sequence of these antigenic peptides. 3. Determine the sites where antigenic peptides are bound. Preliminary results have shown the success of mass spectrometry in sequencing peptides isolated from GRP 94 by HPLC. One peptide has been sequenced by MALDI/PSD MS. Further work will hopefully fulfill our goal.